Staff Software Engineer, Web Application Services

The posting, as Mozilla wrote it

Why Thunderbird?

Thunderbird is one of the world’s most trusted open-source email applications, empowering more than 20 million people globally. At Thunderbird, we build privacy-respecting communication and productivity tools that help people manage their digital lives while staying in control of their data.

We are open source by design. Our products are developed transparently and in collaboration with a global community of contributors, and that same spirit shapes how we work: collaboratively, inclusively, and with a shared commitment to putting users first.

Our small but growing distributed team includes more than 65 people across seven countries. As Thunderbird evolves beyond a single desktop application, we are expanding across desktop, mobile, paid services, AI offerings, and enterprise-facing work to build independent, privacy-respecting alternatives to big tech ecosystems.

Our revenue model combines user donations, which help keep Thunderbird’s applications freely available, with paid services that cover the costs of hosted offerings while supporting long-term sustainability and continued innovation.

A note about Thunderbird and Mozilla: Thunderbird Technologies Corporation is the nonprofit-owned company behind Thunderbird email and a growing portfolio of products. While part of the Mozilla family, Thunderbird is a separate entity from Mozilla Corporation and Mozilla Foundation with its own compensation programs, benefits, and employment policies.

To learn more, visit www.thunderbird.net

The opportunity

As a Staff Software Engineer, Services, you’ll help shape the architecture and technical direction of web-based products that extend Thunderbird beyond email. The Services team is currently focused on building offerings such as an appointment calendar and secure file storage and transfer solutions, creating valuable experiences for our users while supporting additional revenue streams for Thunderbird.

This is a Staff-level individual contributor role with significant technical ownership and influence. You’ll work with designers, engineers, and community members to write code, build prototypes, solve complex problems, and make technical decisions that shape our products. You’ll take a holistic view of our code and systems, helping establish the architecture and software patterns that allow our Services products to evolve and scale.

You’ll also take on broad, ambiguous problems that have a direct impact on our goals, from improving our technical architecture to helping grow Services users and subscribers. Along the way, you’ll provide technical and product direction across teams, mentor other engineers, and identify ways to make our systems and processes more sustainable, scalable, and easier to work with.

What you’ll do

• Lead the technical architecture of new Services products, taking ownership of complex projects and identifying improvements that strengthen our systems as they evolve.
• Write code, build prototypes and e

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. And, we do not provide visa sponsorship.

How to apply

Please apply directly through our career page . We carefully review every cover letter and screening question, so take the time to answer each fully. We value authentic, thoughtful responses that reflect your own experience and perspective. It is fine to use AI tools to polish your writing, but your answers should be your own. Candidates who submit generic or unoriginal AI-generated responses may be disqualified from further consideration.

Our commitment to diversity, equity, and inclusion

Thunderbird believes in the value of diverse creative practices and forms of knowledge, and knows diversity, equity and inclusion are crucial to and enrich the company’s core mission. We encourage applications from everyone, including members of all equity-seeking communities, such as (but not limited to) women, racialized and Indigenous persons, persons with disabilities, persons of all sexual orientations, gender identities and expressions.

We are an equal opportunity employer. We do not discriminate on the basis of race (including hairstyle and texture), religion (including religious grooming and dress practices), gender, gender identity, gender expression, color, national origin, pregnancy, ancestry, domestic partner status, disability, sexual orientation, age, genetic predisposition, medical condition, marital status, citizenship status, military or veteran status, or any other basis covered by applicable laws. Thunderbird will not tolerate discrimination or harassment based on any of these characteristics or any other unlawful behavior, conduct, or purpose.

We will ensure that qualified individuals with disabilities are provided reasonable accommodations to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment, as appropriate. Please contact us at hiringaccommodations@thunderbird.net to request accommodation.

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